ninja'd, but perhaps not entirely...
As advised above, building your own isn't hugely difficult. Having done this many times I must say that certain steps are critically sensitive so must be done well. Installation of the CPU and it's heat-removal fixture comes to mind immediately. Cables can be figured out without much room for serious problems if you take your time, imo. I agree that you will learn a great deal in that process.
If you'd like to consider going with a pre-built PC, there are numerous PC builders out there that cater to the gaming crowd offering anything from modest performance* all the way to the nth degree of performance (and cost, obviously). They will use name-brand, well-regarded, quality components. If you search for a gaming PC on amazon, you'll start to see some products from those kinds of builders. It's a start, especially for those who don't 'know the marketplace' that well, or at all. Once you begin to investigate those builders, you'll likely begin to find more of them in that space. It's not terribly useful for me to recommend specific builders because I'm not aware of your location, nor would I necessarily know any in a location that is useful for you.
As far as I remember, HDMI supports only up to 60Hz refresh rate, so don't go buying a high-end GPU expecting to push 100Hz over an HDMI connection. Buy it to support the graphics needs of the software, yes, but not to try that with a television display. You must use a 'DisplayPort' connection to support high refresh rates (and have a display that allows it, of course).
I can corroborate: I use a Razer Woverine X-Box controller on my Windows PC all the time. It works flawlessly (I use it wired).
* this significantly above anything that you'd get as a PC 'for e-mail and internet browsing.' Don't even consider anything like this (from places like Wally-world, etc.) to run EDO and forget about any 'integrated graphics' imo.